This research will seek to determine the interactions between indigestible plant fiber, which is consumed in the diet, and the secretion rate and availability of digestive enzyme activity. This objective will be approached primarily through studies of 1) In vitro interactions of plant fibers with pepsin, trypsin, chymotrypsin, and lipase. 2) Secretion of the pancreatic enzymes in response to plant fibers themselves and as a dietary component. 3) The activity of pepsin, trypsin, chymotrypsin, lipase, alpha-amylase, and intestinal peptidase activity in the gut contents of fiber-fed animals. Specific plant fibers to be investigated include wheat bran, pectin, and cellulose.